Fuel injection valve for internal combustion engines

ABSTRACT

A fuel injection valve has a valve body and a valve member axially movable within the valve body. The opening stroke of the valve member is limited by a stroke stop face provided on a control piston which surrounds the valve member. A control chamber, which may be filled with fuel, is located at one end of the control piston. At a certain pressure in the control chamber, the control piston moves from a first to a second stroke position to limit the opening stroke motion of the valve member. Part of the control piston is embodied as a piezoelectric actuator which, when supplied with electric current, changes its axial length to further vary the stroke of the valve member.

PRIOR ART

The invention is based on a fuel injection valve for internal combustionengines as generically defined by the preamble to claim 1. One such fuelinjection valve, known from German Patent Disclosure DE 196 23 211 A1,has a valve body in which, in a bore, a piston like valve member isdisposed such that it is movable axially counter to the force of aclosing spring. On the end toward the combustion chamber, the valvemember changes over into a closing head, which is guided in the bore. Inthe outward-oriented opening stroke motion of the valve member, theclosing head emerges from the bore, and a control edge embodied on theclosing head uncovers at least one injection opening. A plurality ofinjection openings can also be provided, which are opened successivelyby the control edge. As a result, by a limitation of the opening strokeof the valve member to a partial stroke, it becomes possible to uncoveronly some of the injection openings or to open only a partial crosssection of one injection opening, and thus to control the entireeffective injection cross section as a function of the opening stroke ofthe valve member. The opening stroke motion is limited to a partialstroke by a control piston, disposed in the valve body, whose end facedefines a hydraulic control chamber. The control chamber can be filledwith fuel at high pressure and as a result can displace the controlpiston axially from a first stroke position to a second stroke position,as a result of which the valve member executes either the maximum strokeor only a partial stroke. A hydraulically adjustable stroke stop of thistype has a black-and-white function; that is, it does not allow anygraduations between the two opening strokes. This limits the controlcapability of the fuel injection event, making further optimization ofthe injection event more difficult.

In a fuel injection valve of the inward-opening type as well, such asthat known from German Patent Disclosure DE 197 29 843, it can bedesirable for the sake of precise metering of a preinjection quantity tohave a partial stroke available that has more than a black-and-whitefunction, allowing an optimal injection course to be attained.

ADVANTAGES OF THE INVENTION

The fuel injection valve of the invention for internal combustionengines, having the characteristics of the body of claim 1, has theadvantage over the prior art that between the closing spring and theguided portion of the valve member, a combined hydraulically andpiezoelectrically controlled stroke stop is embodied, with which theopening stroke motion of the valve member can be set to any valuebetween the maximum opening stroke and the partial stroke. By combiningthe hydraulically adjustable piston with a piezoelectric actuator, it ispossible to switch the hydraulic piston not only between maximum strokeand partial stroke but also, by the delivery of electric current to thepiezoelectric actuator, to switch it between the partial stroke and anyarbitrary value between partial stroke and the maximum opening stroke ofthe valve member. As a result, in a further performance graph range ofthe engine, an optimally adapted opening stroke of the valve member isfeasible. If switching between only partial stroke and a maximum openingstroke is necessary, then the piezoelectric actuator need not besupplied with electric current, which is advantageous from an energystandpoint.

Besides the use of the combined hydraulic and piezoelectricallycontrolled stroke stop in an outward-opening vario-nozzle, it is alsopossible to use the subject of the invention in an inward-opening fuelinjection valve in the same advantageous way.

In an advantageous feature of the stroke stop, the control piston isembodied as a hollow cylinder, on the end of which remote from thecombustion chamber the piezoelectric actuator is disposed.

This makes it easy to mount the control piston, since the piezoelectricactuator and the non-piezoelectrically active part of the control pistoncan be installed separately. In a control piston embodied in this way,in a further advantageous feature, the valve member in the openingstroke motion does not come into direct contact with the piezoelectricactuator but only with the interposition of a shim. This results in lesswear on the piezoelectric actuator and thus a longer service life of thehydraulic stroke stop. Furthermore, the shim offers the capability, byreplacement of this simple and hence economically produced shim, ofsetting the maximum opening stroke precisely by way of the thickness ofthe shim.

In a further advantageous feature, the control pressure for controllingthe hydraulic stroke stop is drawn from a control line, whichcommunicates with a high-pressure reservoir via a control valve.Furthermore, via a further control valve, the control line communicateswith the largely pressureless fuel tank, so that by suitably triggeringthe two valves, loading and relieving of the control line are possible,without requiring a further high-pressure fuel source.

Further advantages and advantageous features of the subject of theinvention can be learned from the description, drawing and claims.

DRAWING

One exemplary embodiment of the fuel injection valve according to theinvention for internal combustion engines is shown in the drawing andwill be described in further detail in the ensuing description. Shownare

FIG. 1, a longitudinal section through the fuel injection valve;

FIG. 2, an enlarged view of the detail marked II in FIG. 1, in theregion of the closing head;

FIG. 3, an enlarged view of the detail marked III in FIG. 1, in theregion of the stroke stop;

FIG. 4, the schematic layout of the fuel supply system for fuelinjection and for furnishing fuel control pressure for the hydraulicallyadjustable stroke stop; and

FIG. 5, a fuel injection valve of the invention, of the inward-openingtype, in longitudinal section.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

FIG. 1 shows a fuel injection valve for internal combustion engines ofthe outward-opening type. In a valve body 1, which can be constructed inmultiple parts, a bore 2 is made in which a piston like valve member 5is disposed, which is axially movable counter to the force of a closingspring 21. In a portion, shown at the top in FIG. 1, of the bore 2 thatis remote from the combustion chamber, the valve member 5 is guided,while the portion of the valve member 5 remote from the combustionchamber and shown at the bottom in FIG. 1 is surrounded by a pressurechamber 11, which can be made to communicate with a high-pressure fuelsource via an inlet conduit 3 embodied in the valve body 1. The valvemember 5 merges toward the combustion chamber with a larger-diameterclosing head 10, which is guided in a larger-diameter portion of thebore 2.

In FIG. 2, an enlarged view of the closing head 10 and the surroundingvalve body 1 is shown. On the outer wall of the closing head 10, tworows of injection openings 13 a and 13 b are provided, with one rowincluding all the injection ports that are disposed at the same heightas the closing head. The injection openings 13 a and 13 b communicatewith the pressure chamber 11 via injection conduits 12, which areembodied in the closing head 10. In the closed state of the fuelinjection valve, a valve sealing face 15 embodied on the closing head 10comes to rest on the face end of the valve body 1, which end is embodiedas a valve seat face 17, and the injection openings 13 a, 13 b arecovered by the valve body 1. Because the diameter of the closing head 10is larger in comparison to the valve member 5, a pressure shoulder 18 isembodied on the end of the closing head 10 remote from the combustionchamber, and this shoulder is exposed to the fuel pressure in thepressure chamber 11. As an alternative to the embodiment shown in FIG.2, it can also be provided that more than two rows of axially offsetinjection openings 13 a, 13 b are disposed on the outer jacket face ofthe closing head 10. In a further embodiment, it can also be providedthat only one rows of injection openings 13 a, 13 b is provided on theouter jacket face of the closing head 10, and the cross section of thisrow is opened either entirely or only in part in the opening strokemotion of the valve member 5.

On its end remote from the combustion chamber, the valve member 5changes over into a spring tappet 24, which protrudes as far as theinside of a spring chamber 20 embodied in the region of the valve body 1remote from the combustion chamber. On the end of the spring tappet 24remote from the combustion chamber, a spring plate 23 is embodied, onwhich the closing spring 21 is braced by its end remote from thecombustion chamber. The spring chamber 20 communicates, via an outletconduit embodied in the valve body 1 but not shown in the drawing, withan outlet line in order to carry away the leaking oil entering thespring chamber 20.

FIG. 3 shows an enlarged view of the adjustable stroke stop of FIG. 1.Between the guided portion of the valve member 5 and the spring chamber20, a larger-diameter guide bore 6 is formed. Disposed in the guide bore6 are a control stop 31, connected to the valve body 1, and a controlpiston 30, which is movable axially in the guide bore 6. The controlstop 31 is disposed on the end of the guide bore 6 remote from thespring chamber 20 and is embodied as a hollow cylinder, whose insidediameter is graduated, with the portion having the larger insidediameter being toward the spring chamber 20. The control piston 30 islikewise embodied as a hollow cylinder, and its outer diameter isgraduated, and the portion having the smaller diameter is located remotefrom the spring chamber 20. The portion of the control piston 30 havingthe smaller outer diameter plunges into the portion of the control stop31 of larger inside diameter, and between the control piston 30 and thecontrol stop 31, a throttle gap 45 is formed. The outer annular end face35, formed on the control piston 30 toward the combustion chamber by thegraduated outer diameter, on the one hand and the control stop 31 on theother define a control chamber 33, to which a control conduit 34 extendsthat is embodied in the valve body 1. Via the throttle gap 45, onlylittle fuel can flow from the control chamber 33 past the valve member 5into the spring chamber 20. The control piston 30 is constructed in twoparts; the hollow-cylindrical portion toward the spring chamber 20 isembodied as a piezoelectric actuator 26, and the other part forms agraduated hydraulic piston 27. For delivering electric current to thepiezoelectric actuator 26, suitable electrical contacts are disposed onit, which are connected to a suitable voltage source via an electricline, not shown in the drawing. The electric line can for instance beguided in a separate conduit embodied in the valve body 1, or it can beextended to the outside through the spring chamber and the outletconduit, not shown in the drawing, of the spring chamber 20.

Toward the spring chamber 20, a support disk 25 is disposed on thepiezoelectric actuator 26, and its face end toward the spring chamber 20is embodied as a stroke stop face 42, which in the stroke motion of thecontrol piston 30, oriented toward the spring chamber 20, comes to reston a control piston stop 43 formed by the cross-sectional reduction fromthe guide bore 6 to the spring chamber 20. A spring support ring 22 isdisposed in the spring chamber 20, and the closing spring 21 is bracedon this ring by its end toward the combustion chamber. The springsupport ring 22 is guided in the spring chamber 20 and is pressedagainst the support disk 25 by the force of the closing spring 21. Atthe transition from the valve member 5 to the spring tappet 24, aannular collar 40 extending all the way around is embodied on the valvemember 5; its annular end face toward the combustion chamber is embodiedas a stop face 41. In the opening stroke motion of the valve member 5oriented toward the combustion chamber, this stop face 41 comes to reston the stroke stop face 42 embodied on the shim 25, thereby defining theopening stroke.

In FIG. 4, the layout of the high-pressure fuel supply is shownschematically. From a fuel tank 50, fuel is delivered via a low-pressureline 51 to a high-pressure fuel pump 52. The high-pressure fuel pump 52pumps fuel at high pressure through a high-pressure line 5 into ahigh-pressure reservoir 55. For each fuel injection valve 101 of theinternal combustion engine, one fuel inlet line 60 leads away from thehigh-pressure reservoir 55 and communicates at the fuel injection valve101 with the inlet conduit 3. Between the inlet conduit 3 and the fuelinlet line 60, there is a metering valve 67, with which thecommunication from the high-pressure reservoir 55 to the inlet conduit 3can be opened or closed. The high-pressure reservoir 55 can be made tocommunicate with a control line 58 via a control valve 57. Since acertain high fuel pressure is always maintained in the high-pressurereservoir 55, by opening the control valve 57 fuel can be carried athigh pressure into the control line 58, as a result of which thepressure in the control line 58 adapts to that in the high-pressurereservoir 55. Each fuel injection valve 101 communicates with thecontrol line 58 via a control inlet line 59 that communicates with thecontrol conduit 34 in the valve body 1. The control line 58 can be madeto communicate with the fuel tank 50, acting as a relief chamber, via anoutlet line 63 in which a control valve 61 is disposed. By opening thecontrol valve 61, the pressure in the control line 58 can be relieved atany time to the pressure level of the fuel tank 50, which isapproximately equivalent to atmospheric pressure. The entire fuelinjection system is controlled by a control unit 65, which includes acomputer, which by means of the measured values of various sensors, notshown in the drawing, controls the high-pressure fuel pump 52, thecontrol valves 61 and 57, the metering valves 67, and the supply ofelectric current to the piezoelectric actuator 26.

The mode of operation of the fuel injection valve shown in FIG. 1 is asfollows:

At the onset of the injection event, the metering valve 67 opens thecommunication from the fuel inlet line 60 to the inlet conduit 3. As aresult, fuel flows out of the high-pressure reservoir 55 through thefuel inlet line 60 and the inlet conduit 3 into the pressure chamber 11.The fuel pressure in the pressure chamber 11 rises, until the resultantforce in the axial direction on the pressure shoulder 18 is greater thanthe force of the closing spring 21. The valve member 5 moves outwardtoward the combustion chamber, and as a result the two injectionopenings 13 a and 13 b emerge in succession from the bore 2, as a resultof which the pressure chamber 11 communicates with the combustionchamber, and fuel is injected into the combustion chamber. By means ofthe outward-oriented opening stroke motion of the valve member 5, theannular collar 40 also moves toward the combustion chamber, and thus thestop face 41 moves toward the stroke stop face 42. Whether the valvemember 5 executes the maximum stroke h or only a partial stroke dependson the status of the control piston 30.

The mode of operation of the adjustable stroke stop is as follows:

In the closed state of the fuel injection valve, that is, when the valvesealing face 15 is in contact with the valve seat face 17 and when thecontrol chamber 33 of the hydraulic stroke stop is pressureless andthere is no current to the piezoelectric actuator 26, the stroke stopface 42 has an axial spacing from the stop face 41 of the annular collar40 that is equivalent to the maximum opening stroke h of the valvemember 5. This status is shown in the left half of FIG. 3. If thecontrol chamber 33 is without fuel pressure, then the inner annular endface 36 of the control piston 30 is in contact with the seat face 37 ofthe control stop 31. If then, with the control valve 57 open and thecontrol valve 61 closed, fuel is introduced into the control chamber 33via the control conduit 34, the pressure in the control chamber 33 thenrises until the resultant force on the outer annular end face 35 isgreater than the force of the closing spring 21. The control piston 30moves toward the spring chamber 20, until after the execution of thecontrol stroke s, it comes to rest with the stroke stop face 42 on thecontrol piston stop 43. This status is shown in the right half of FIG.3. The control stroke s is shorter than the maximum opening stroke h. Inthe opening stroke motion of the valve member 5, the stop face 41, afterthe execution of the stroke h-s, comes to rest on the stroke stop face42. The control stroke s amounts to approximately 30 to 70% of themaximum opening stroke h, so that by subjecting the control chamber 33to pressure with the resultant stroke motion of the control piston 30,the opening stroke motion of the valve member 5 is limited to from 70 to30% of the maximum opening stroke h. If the valve member 5 is meant toexecute the maximum opening h again, then the pressure in the controlchamber 33 is reduced by relief of the control line 58 into the fueltank 50, with the control valve 57 closed, via the control valve 61 andthe outlet line 63. If the force of the closing spring 21 exceeds theforce of the fuel pressure on the inner annular end face 36 of thecontrol chamber 33, then the control piston 30 is pressed toward thecombustion chamber by the closing spring 21, until the inner annular endface 36 rests on the seat face 37. If the stroke stop face 42 is meantto execute only a portion of the control stroke s, then current issupplied to the piezoelectric actuator 26. Because of the change inlength of the piezoelectric actuator 26 in response to the voltageapplied, the stroke stop face 42 can be raised continuously variably toany arbitrary portion of the control stroke s. The maximum possiblechange in length of the piezoelectric actuator 26 is then equivalentapproximately to the control stroke s, for instance.

In FIG. 5, a fuel injection valve of the invention of the inward-openingtype is shown in longitudinal section. A bore 90 embodied as a blindbore is disposed in a valve body 80, and its bottom face is orientedtoward the combustion chamber. A conical valve seat 83 is embodied onthe bottom face along with at least one injection opening 92, whichconnects the bore 90 with the combustion chamber. By means of a lock nut98 and with the interposition of a shim 94, the valve body 80 is bracedagainst a valve holding body 96, which can be constructed in multipleparts.

A pistonlike valve member 100 that is longitudinally adjustable counterto the force of a closing spring 21 is disposed in the bore 90; it isguided in sealing fashion in a portion of the bore 90 remote from thecombustion chamber, and toward the combustion chamber, it changes overinto a portion of smaller diameter, forming a pressure shoulder 88. Onthe end toward the combustion chamber, a valve sealing face 81 is formedon the valve member 100, which face cooperates with the valve seat 83and thus opens and closes the injection openings 92 by means of thelongitudinal motion of the valve member 100. The pressure shoulder 88 isdisposed in a pressure chamber 11, embodied in the valve body 80, whichchamber continues, toward the valve seat 83, into an annular gapsurrounding the valve member 100 and can be filled with fuel via aninlet conduit 3 embodied in the valve body 80. By the hydraulic force onthe pressure shoulder 88, the valve member 100 can be moved within thebore 90, counter to the force of the closing spring 21, so that theinjection openings are opened.

On the end remote from the combustion chamber, the valve member 90changes into a spring plate 103 and adjoining that into a spring tappet107, both of which are disposed in a spring chamber 105 embodied in thevalve holding body 96. The spring chamber 105 is embodied with agraduated diameter and is enlarged toward the end remote from thecombustion chamber, forming a control piston stop face 43 embodied as anannular shoulder.

On the end of the spring chamber 105 remote from the combustion chamber,a combined hydraulically and piezoelectrically controlled stroke stop isprovided, of the kind already described above in the description of theoutward-opening fuel injection valve of FIGS. 1 and 3, so that only somedetails of it need to be addressed here. Toward the combustion chamber,the control piston 30 is disposed toward the control stop 31, and theclosing spring 21 surrounding the spring tappet 107 is disposed betweenthe control piston's face end toward the combustion chamber and thespring plate 103 and, with the valve sealing face 81, presses the valvemember 100 against the valve seat 83. The valve member 100, on its endremote from the combustion chamber, has a stop face 109, which as aresult of the opening stroke motion of the valve member 100 in thedirection away from the combustion chamber comes to rest on the controlpiston 30. Upon activation of the hydraulic stop or piezoelectricactuator, the control piston 30 moves counter to the force of theclosing spring 21; the control piston stop face 43 defines the maximumpath of the control piston 30. As a result, the stroke stop face 42embodied on the control piston 30 is displaced as well and thus reducesthe maximum possible opening stroke of the valve member 100.

Alternatively to the hydraulic stroke stop shown in FIG. 3 or FIG. 5, itcan also be provided that the entire control piston 30 is embodied as apiezoelectric actuator. Then there is no need for connecting thepreferably metal hydraulic piston 27 to the piezoelectric actuator 26.It can also be provided that the support disk 25 is omitted and that thestroke stop face 42 is embodied on the piezoelectric actuator 26.

It should be noted in FIGS. 1, 3 and 5 that the piezoelectric actuator26 has been shown only schematically, for the sake of simplicity. Thesize and in particular the axial length of the piezoelectric actuator 26must be selected to suit the particular application, taking into accountthe slight relative change in length of the piezoelectric actuator.

What is claimed is:
 1. A fuel injection valve for an internal combustionengine comprising: a valve body (1, 80) having an axially extending bore(2), a piston like valve member (5, 100) movable axially within saidbore (2) counter to a closing force, said valve member being guided insaid bore (2) over a portion of its length and controlling at least oneinjection opening (13 a, 13 b, 92), which can be opened entirely or inpart by an opening stroke motion of said valve member (5, 100), apressure chamber (11) formed in said valve body surrounding a portion ofsaid valve member and adapted for connection with a high-pressure fuelsource (55), a pressure shoulder (18) formed on said valve member andbeing located within said pressure chamber whereby connection of saidpressure chamber to said high-pressure fuel source exposes said pressureshoulder to high-pressure causing said valve member to initiate itsopening stroke motion counter to said closing force and said at leastone injection opening to communicate with said pressure chamber (11),and an axially moveable control piston (30), defining the maximumopening stroke of the valve member (5, 100), one end face of saidcontrol piston acting as a stroke stop face (42) to limit the openingstroke motion of said valve member (5, 100) and an opposite end face(35) of said control piston defining a control chamber (33) adapted forconnection to said high-pressure fuel source, the improvement whereinsaid control piston (30) comprises a piezoelectric actuator (26).
 2. Thefuel injection valve of claim 1, wherein said valve member (5, 100) isformed with a stop face (41, 109) which, in the opening stroke motion ofthe valve member, comes to rest on the stroke stop face (42) of saidcontrol piston (30).
 3. The fuel injection valve of claim 2, wherein thecontrol piston (30) comprises a hollow cylinder, which is disposedcoaxially to the valve member (5, 100) and is guided in a guide bore (6)in said valve body.
 4. The fuel injection valve of claim 3, wherein thecontrol piston (30) comprises a stepped piston having portions ofdifferent diameters, including a larger diameter portion having an endface located near the stop face (41, 109) of said valve member (5, 100)and serving as said stroke stop face (42), and a smaller diameterportion having an end face (35) remote from the stroke stop face (42)which defines a wall of said control chamber (33).
 5. The fuel injectionvalve of claim 4, wherein the piezoelectric actuator (26) comprises ahollow cylinder and is disposed coaxially to the valve member (5, 100).6. The fuel injection valve of claim 5, wherein only a part of thecontrol piston (30) is formed by the piezoelectric actuator (26), andthe piezoelectric actuator (26) is disposed such that it is orientedtoward the stop face (41, 109) of the valve member (5, 100).
 7. The fuelinjection valve of claim 6, wherein the valve member (5), to open theinjection openings (13 a, 13 b), executes said opening stroke motionoriented outward, toward a combustion chamber of said internalcombustion engine when the fuel injection valve is mounted on theengine.
 8. The fuel injection valve of claim 7, wherein the valve member(5) includes an annular collar (40) having an annular end face, which isoriented toward the combustion chamber of said internal combustionengine when the fuel injection valve is mounted on the engine, andserving as the stop face (41), which cooperates with the stroke stopface (42) of the control piston (30).
 9. The fuel injection valve ofclaim 3, wherein the valve member (5), to open the injection openings(13 a, 13 b), executes said opening stroke motion oriented outward,toward a combustion chamber of said internal combustion engine when thefuel injecting valve is mounted on the engine.
 10. The fuel injectionvalve of claim 9, wherein the valve member (5) includes an annularcollar (40) having an annular end face, which is oriented toward thecombustion chamber of said internal combustion engine when the fuelinjection valve is mounted on the engine, and serving as the stop face(41), which cooperates with the stroke stop face (42) of the controlpiston (30).
 11. The fuel injection valve of claim 3, wherein thecontrol chamber (33) is adapted to communicate with the high-pressurefuel source (55) via a control valve (57).
 12. The fuel injection valveof claim 11, wherein the control chamber (33) is adapted to communicatewith a relief chamber (50) via a control valve (61).
 13. The fuelinjection valve of claim 12, wherein the high-pressure fuel source isembodied as a high-pressure reservoir (55).
 14. The fuel injection valveof claim 2, wherein the control piston (30) includes a support disk (25)disposed at an end face of the control piston (30) toward the stop face(41, 109) of the valve member (5, 100), and a face of said a supportdisk (25) serves as the stroke stop face (42).
 15. The fuel injectionvalve of claim 14, wherein the valve member (5), to open the injectionopenings (13 a, 13 b), executes said opening stroke motion orientedoutward, toward a combustion chamber of said internal combustion enginewhen the fuel injection valve is mounted on the engine.
 16. The fuelinjection valve of claim 14, wherein the control chamber (33) is adaptedto communicate with the high-pressure fuel source (55) vial a controlvalve (57).
 17. The fuel injection valve of claim 2, wherein saidclosing force is supplied by at least one closing spring (21) disposedin a spring chamber (20, 105) in said valve body.
 18. The fuel injectionvalve of claim 17, wherein the control piston (30) is guided in a guidebore (6) adjacent said spring chamber (20) in said valve body, saidguide bore (6) having a larger diameter than said spring chamber (20)and an annular end face (43) at the transition from the guide borediameter to the spring chamber diameter, which limits the axial motionof the control piston (30) in the direction of the stop face (41, 109)of the valve member (5, 100).
 19. The fuel injection valve of claim 18,wherein the closing spring (21) rests at least indirectly on the strokestop face (42) of the control piston (30), so that the closing spring(21) acts counter to the stroke of the control piston (30).
 20. The fuelinjection valve of claim 17, wherein the closing spring (21) rests atleast indirectly on the stroke stop face (42) of the control piston(30), so that the closing spring (21) acts counter to the stroke of thecontrol piston (30).
 21. The fuel injection valve of claim 1, whereinthe valve member (5), to open the injection openings (13 a, 13 b),executes said opening stroke motion oriented outward, toward thecombustion chamber of said internal combustion engine when the fuelinjection valve is mounted on the engine.
 22. The fuel injection valveof claim 21, wherein the valve member (5) includes an annular collar(40) having an annular end face, which is oriented toward the combustionchamber of said internal combustion engine when the fuel injection valveis mounted on the engine, and serving as a stop face (41), whichcooperates with the stroke stop face (42) of the control piston (30).23. The fuel injection valve of claim 1, wherein the control chamber(33) is adapted to communicate with a high-pressure fuel source (55)vial a control valve (57).
 24. The fuel injection valve of claim 23,wherein the control chamber (330 is adapted to communicate with a reliefchamber (50) via a control valve (61).
 25. The fuel injection valve ofclaim 23, wherein the high-pressure fuel source is embodied as ahigh-pressure reservoir (55).